How long is secondary school?

Could you tell me how long secondary school typically lasts? I’m asking in the context of standard educational systems, specifically referring to the period of schooling that follows primary or elementary education and precedes higher education like college or university. I understand that the exact duration can vary—some regions have a single phase while others split it into lower and upper levels—but I’m curious about the most common structure and total years involved in completing secondary education. For example, does it usually span 4 to 6 years, or is there a standard benchmark across most countries?

The length of secondary school varies significantly by country, but common durations include:

• United States: Typically 4 years (Grades 9-12).
• United Kingdom: 5 to 7 years secondary education. Compulsory secondary (Key Stages 3 & 4) is 5 years (ages 11-16), often followed by 2 years of optional post-16 education (Key Stage 5, ages 16-18).
• Canada: Varies by province/territory, commonly 4 to 5 years (Grades 9-12 or 8-12).
• Australia: Varies by state/territory, typically 5 to 6 years (often Year 7/8 to Year 12).
• New Zealand: 5 to 7 years (commonly Year 9 to Year 13).
• Singapore: 4 to 5 years secondary education (Secondary 1 to Secondary 4/5, leading to O-Level exams; followed by 2-3 years at a junior college/polytechnic).
• Republic of Ireland: Typically 5 to 6 years (1st Year to 6th Year, leading to Leaving Certificate).
• France: 4 years (collège: ages 11-15, followed by lycée: ages 15-18 for baccalauréat).
• Germany: 6 to 7 years (Sekundarstufe I: ages 10-16, followed by Sekundarstufe II: ages 16-19 for university entrance or vocational qualifications).
• Japan: 3 years (Lower Secondary: ages 12-15, followed by Upper Secondary: ages 15-18).
• China: 3 years (Junior High: ages 12-15, followed by Senior High: ages 15-18).
• Russia: 5 years (Years 5-9, ages 11-15), followed by 2 years (Years 10-11, ages 15-17) for the Attestat Srednego Obshchego Obrazovaniya (Certificate of Secondary Education).

Most systems require secondary education to be completed between ages 14/15 and 17/18.